Golgi apparatus function in animal cells: The Golgi apparatus plays an important role in eukaryotic cells by performing various functions. The main functions of the Golgi apparatus in animal cells include:
- Post-translational modification
- Sorting, and packaging of proteins
- Lipid metabolism
- Lysosomes formation etc.
| Functions | Description |
| Protein Modification and packaging | · Processes and modifies proteins synthesized in the endoplasmic reticulum.
· It Sorts and packages proteins into vesicles for transport within or outside the cell. |
| Lysosomes and Secretory Vesicles formation | · Produces lysosomes and secretory vesicles |
| Lipid Modification | · Forms lipoproteins for membrane structure. |
| Modulation of Membrane Proteins | · Modifies and processes membrane proteins for correct localization and function. |
| Recycling of Membrane Components | · Recycles specific membrane components and receptors for cell turnover. |
| Calcium Storage | · Stores and releases calcium ions which are essential for cell signaling and muscle contraction. |
Let us discuss the functions of Golgi apparatus in detail.
Role in post translational modification:
- Proteins synthesized in the endoplasmic reticulum (ER) undergo various modifications in the Golgi apparatus so that it becomes fully functional. These modifications include following process:
| Process | Description |
| Glycosylation | · Addition of sugar molecules to the proteins.
· Glycoproteins are often formed through this process. |
| Phosphorylation | · Addition of phosphate groups to specific amino acids present in the proteins.
· It is commonly used mechanism for the regulation of protein activity and cellular signaling. |
| Sulfation | · Addition of sulfate groups to specific amino acids in proteins.
· This is important for the functioning of certain proteins |
| Acetylation | · Addition of acetyl groups to certain amino acids
· It is often involved in the regulation of gene expression and protein stability. |
| Methylation | · Addition of methyl groups to specific amino acids and influences protein-protein interactions as well as gene regulation. |
| Ubiquitination | · Attachment of ubiquitin molecules to the proteins.
· It marks them for specific cellular processes e.g. endocytosis. |
| Proteolytic Cleavage | · Removal of specific peptide segments from proteins.
· This process either activate them or modify their function e.g. activation of enzymes. |
Role in protein sorting:
- The Golgi apparatus acts as a sorting center for proteins.
- It sorts proteins destined for the lysosomes, plasma membrane, or secretions outside the cell.
- Proteins that are intended for secretion outside the cell are sorted into secretory vesicles.
- These vesicles bud off from the Golgi’s cisternae and move to their respective destinations within the cell.
Role in lysosome formation:
- The Golgi apparatus is crucial for the synthesis of lysosomes, which are responsible for intracellular digestion and recycling of cellular waste.
- Enzymes that are important for lysosomal function are processed and modified within the Golgi apparatus before being transported to lysosomes.
Role in vesicle formation:
- The Golgi apparatus take part in the formation of transport vesicles that carry proteins and lipids to their future destinations.
Role in lipid metabolism:
- Golgi apparatus synthesizes some of the lipids and further modifies the lipids that are received from the ER before transporting them to various cellular membranes.
- It generates lipid components essential for the assembly of cellular membranes.
Role in Secretory pathways:
- The Golgi apparatus is a main component of the secretory pathway that is responsible for transportation of materials from the ER through the Golgi to the plasma membrane for secretion.
- Proteins destined for secretion are sorted into secretory vesicles within the trans-Golgi network. These vesicles are then move toward the plasma membrane. They fuse with the membrane and release their contents through exocytosis.
Role in intracellular communication and cell signaling:
- Golgi apparatus also participates in intracellular communication and cell signaling process.
- Some proteins which are being processed in the Golgi apparatus are involved in signal transduction pathways, which enable cells to respond to various external stimuli and coordinate their activities.